The hot tub industry is dominated by fiberglass shell hot tubs. These are typically self-contained units with all of the piping and associated equipment (pumps, filter, heater and so forth) attached to the outside of a thin fiberglass shell. Such tubs are designed to rest on a concrete slab above ground and require an exterior skirt to conceal the piping and mechanical equipment. They may include a set of wooden steps for entry and exit. These tubs typically utilize small electric pumps, filters and heaters due to size constraints.
There are some fiberglass tubs that are designed to drop into the ground, typically adjacent to swimming pools. These tubs utilize similar construction methods and the exposed piping requires the construction of a concrete bunker to protect the unit from frost and ground movement.
All fiberglass tubs utilize the same type of molded shell and interior gel coating. They are generally limited in durability and are considered depreciable components akin to other outdoor consumer products such as barbecues, patio furniture and so forth. They generally have a life span of seven to ten years and would then require disposal. The interior finishes do not lend themselves to economical refurbishment. Such tubs offer no structural strength and thus cannot support any auxiliary structures, perimeter decking and so forth.
Conventional tubs also cannot be customized beyond a limited selection of interior finish colors. They are also typically limited in depth and perimeter size. They are generally designed to be easily installed without heavy equipment so a tub that is too wide or heavy would be cumbersome and be difficult to install. Further, there are severe limitations on the capabilities of the self-contained heating and filtration systems which necessitates a limited water volume. There are some larger self-contained swim spa hybrids available but they too utilize the same construction techniques and suffer from limited durability, structural integrity and so forth and thus, are also considered a depreciating consumable product.
These conventional fiberglass tubs comprise the vast majority of the hot tub market. There are a few other types of tubs available using other materials such as wood, or vinyl over prefabricated steel but they suffer from many of the aforementioned limitations and comprise a tiny fraction of the spa market.
If a consumer wants a product that does not suffer from the limitations of the fiberglass tubs then he or she will need to move on to a custom concrete hot tub. This is almost always accomplished by contacting a local concrete swimming pool contractor and scheduling an installation. The contractor will then construct a solid concrete tub on the owner's property utilizing either formed and poured concrete or shotcrete concrete placement technology. This type of hot tub, if installed correctly, relieves the aforementioned limitations of the fiberglass tub.
For example, concrete tubs constructed on site utilize mechanical equipment that is located some distance away from the structure. There is typically a piping trench that leads away from the tub to a remote location where the equipment is located. This allows the installation of any type of equipment. Higher quality equipment can be used, permitting larger water volumes and consequently larger, and more elaborate structures. Any type of fuel source can be used for the heating system which dramatically improves efficiency (99 percent of fiberglass tubs use inefficient electric heaters). Larger pumps can be used which increase the performance of the jets. Also, much larger filtration and sanitation systems can be used which improve the ease of maintenance and the water quality in the tub. Many more automation and control options are available with remotely located equipment.
Further, the equipment can be serviced, replaced or updated at any time without affecting the actual structure of the tub. If more technologically advanced componentry becomes available it can be easily installed. This ensures top performance of the tub for decades, as the actual structure of the tub is non-degrading.
Another big advantage of concrete tubs is in the customization and durability of the finishes. Concrete tubs typically utilize a either a formed and poured or natural stone coping (this is the top edge of the tub). They then use a tile interior banding at the water level. This tile is often laid about 12″ wide and then the balance of the hot tub interior is finished in a cementitious material such as plaster or Marbelite. Often, the whole interior of the tub is finished in mosaic tile. Other interior options include solid marble or granite.
As one could imagine, there are an infinite number of combinations for the coping, tile, plaster, marble or granite interior finishes which results in almost every concrete tub being unique. These finishes also offer unparalleled durability if installed correctly. They also lend themselves to easy refurbishment or replacement later on if required.
However, concrete tubs fabricated and poured on site have their own set of limitations.
One limitation stems from the fact that only a small percentage of the market is serviced by a capable concrete contractor. Because the work is all done on site, if a customer is not within close proximity to a reputable concrete swimming pool builder, he or she is out of luck. It is not economical for the builder to travel a long distance to construct the tub as it requires many small processes spread over several weeks. Even if the client has a geographically proximate contractor the builder may lack the technical knowledge to construct the product properly. There are very few building standards in this industry which results in widely disparate product quality.
Assuming that the client can locate a reputable and capable contractor, limitations are caused by the fact that the work will take place on site over a period of several weeks. This is because the construction of the product is quite complex and requires many separate stages, often involving curing time in between steps. This work is, of course, weather permitting, which limits the number of working days, especially in colder climates. The weather can also impact the product quality severely resulting in unacceptable variation.
As mentioned above, there is almost no standardization in the industry, which results in low product consistency. The quality of the product is completely dependent upon the capabilities of the local contractor and the conditions under which the product is installed. There is also the inconvenience and increased cost of a large construction site over a fairly long period of time.
For these reasons, the concrete tub has enjoyed fairly limited traction in the marketplace. Although almost any concrete tub is superior to any preformed fiberglass tub, they are generally plagued by high cost, inconvenience, variable product quality and limited availability.
Therefore, a need exists for a precast concrete tub that eliminates the deficiencies inherent in both conventional pre-constructed fiberglass tubs and concrete hot tubs that are built onsite.